Michael based on your description, I guess thermodynamically, the PGC-150 is not quite as impressive as it first might appear. Because it is cooling a gas from room-temperature down to -95C and uses the paralllel cooling path with the autocascade return refrigerant flow, it provides very little of its total cooling duty at -95C. To cool nitrogen to -95C there is no phase change so it is all sensible heat with an effective heat-transfer temperature of probably only -50C. It would be much harder (probably impossible) to match the PGC-150's COP if you had all the cooling being done by an evaporator at -95C. If all the cooling was done at -95C, it COP would likely be cut in half.

Kevin